Electrolytic device



Nov. 7, 1939. M. KNAB El AL ELECTROLYTIC DEVICE Filed Aug. 4, 1937 INVENTORS MAX KNAB 6Q HAROLD IDANZIGER Patented Nov. 7, 1939 nane sncc'monmo DEVICE Max Knab, Brooklyn, N. Y... and Harold ll. Banziger, Williamstown, Mass, assignors to Spragiie Specialties Company, North Adams, Mass, a corporation of Massachusetts Application August 4. 1937, Serial No. isavzs 5 Claims.

The present invention relates to electrolytic devices and more particularly to improvements in the construction of such devices.

The invention will be described in connection lo the electrode. In'case the electrode lacks rigidity, for example when it consists of a thin foil, the riser also serves as a support for the electrode.

Various riser constructions have been sug- 2o gestecl and used in the past, the most common being rod-shaped risers towhich the electrode was attached by means of bolts, rivets, and like connecting members which pass through corresponding holes of the electrode and riser.

25 Such constructions have several disadvantages; for example the drilling and riveting involve added expenses and furthermore, the holes greatly weaken these members; thus to give the riser sufflcient rigidity it has to be made of a substantial cross-section which further increases the manufacturing costs. I A still more serious objection to such constructions is the large number of contact surfaces incidental to them, there being contact surfaces between the electrodes and the rivets and separate contact surfaces between the rivets and the riser, which correspondingly increase the change for corrosion at the contact surfaces.

An object of this invention is therefore to provide an electrode assembly comprising a rigid riser of great simplicity and which involves small costs of manufacture and assembly.

A further object of the invention is to provide an electrode assembly having a minimum of con- 45 tact surfaces;

Other objects and novel features of the invention will appear as the specification progresses.

According to the invention the riser consists 50 of an aluminum or. other film-forming metal rod or wire which is flattened along its portion adjacent to the electrode. The flattening or this riser portion takes place by compression, which operation at the'same time extrudes from the -55 riser a number of integral projections adapted 'tainer end ii.

(Cl. lid-=31? to form rivets for the electrode. Preferably the riser is also mechanically strengthened by integral ribs forming a backing for-the extruded rivets, and the rivets are provided with distancing shoulders and cutting edges for purposes 5 later to be described.

In the drawing forming part of the specification:

. Figure l is a partly sectionized side elevation of an electrolytic condenser embodying the invention;

Fig. 2 is a top view of the anode assembly;

Fig. 3 is a front elevation of an anode riser made according to the invention;

Fig. 4 is a side elevation of the anode riser of 5 a elevation oi the anode riser of 6 is an enlarged scale view or" a portion of showing the details of the rivet construc- Fig. 7 is a cross-sectional view taken along the line TL-i oi 6.

Referring to the drawing, the condenser shown in Fig. 1 comprises a cylindrical metallic container l9, which preferably constitutes the oathode of the condenser, and which may be either of film-forming or-non-film-iorming metal. The container iii is provided with a reduced tubular extension i2, threaded i3 and extending into so a further reduced tubular portion i l.

The anode assembly it consists of a corrugated thin ioil E6 of aluminum or other film-- forming metal, having the shape of an accordion pleating, and is secured to the anode riser ill to be later more fully described.

The top of the container is provided with a crowned metal cap it: which fits into the coni l vent gasket l9 of suitable material, for example of wax-impregnated cloth, 4 is interposed between the container Hi and the cap it. The free edge of the cap it, with the gasket is interposed, is crimpedover the rim provided on the container ill to form a liquidti'ght seal.

To prevent the anode foil it from contacting with the container it, there is interposed between same and the anode assembly l5 an insulator, for instance, a thin hard rubber cylinder 20. To permit free circulation of the electrolyte between cathode and anode, the insulator 20 is provided with perforations 2i throughout its area.

The threads IS on the reduced neck portion H are adapted to receive a nut (not shown) 'by means of which the condenser may be secured to a suitable base.

The extension ll has preferably the same inside diameter as the extension l2, so that the two form a common bore 22; the wall of the extension I4 is however preferably much thinner than the wall of extension l2.

Placed in the bore 22 is a tightly-fitting plug 28 preferably of semi-hard vulcanized rubber 10 through which passes the anode riser IT.

The plug 23 is preferably of such a length as to extend on both sides of the neck portion l4. Proper sealing between the plug 23 and the neck I may be obtained by fluting, as described in 15 U. Si A. Patent No. 1,996,982 to Robert C. Sprague et a A suitable film-maintaining electrolyte 25 is provided in the container, and fills the container close to its top. v

Such an electrolyte comprises as a rule, one or more ionogens and a solvent. As ionogen preferably a combination of a weak acid and salt is used, for instance an electrolyte comprising borax and boric acid or ammonium borate and 35 boric acid, having as solvent water and/or a poly- '30 used, whereby the salts do not need'to be those of the acid used. 1

The viscosity of the electrolyte may range from that of water at 100 C. to that of a paste. A preferred embodiment of the riser of the in- 35 vention is-shown in detail in Figs. 3 to 7. The riser is shaped from an aluminum rod of small diameter, having for example a diameter of $4,". The portion 30 contacting with the electrode I6 is flattened, whereas its downward extending portion II is left round.

Extruded from the section 30 are a plurality of rivets 32 which serve to fixedly hold the electrode foil l6 and make positive electrical connections therewith. The number of rivets depends partic- 45 ularly on the length of the foil II; as a rule we space the rivets about 1" apart.

The rivets 32 are formed with a conical recess [0 to facilitate the riveting and to simplify the anode assembly, as will be explained later. We;

50' also prefer to form the rivets with a shoulder 33 which serves to hold the electrode foil l6 clear from the riser so that the foil can be properly filmed over its entire area except for the small portions directly held by the rivets. The clear- 55 ance so obtained also prevents frictional contact between the electrode foil IO and the riser H, which would cause corrosion of the filmed sur-f faces at such contact points.

In the rear of the rivets 32 the material of the- 60 riser is so deformed as to constitute elongated cavities 34 provided :with longitudinal ribs 35, which reinforce the riser I! at its rivet-carrying portions.

As a rule, as is also indicated in the drawing,

. the rivet-carrying portions II are flattened to" a greater width than are the portions 36 intermediate and adjacent thereto.

The round portion ll of the riser is preferably 1 provided with lengthwise corrugations 31 so oated as to engage the rubber plug 23 when assembled in the condenser, and thus to prevent axial rotation of the riser within the stopper.

To obtain a sturdy construction, we have found it necessary to form the riser with its flattened section 30, the extruded'rivets 32 and shoulders 33, the strengthening rib 35, and the corrugations 31 all in one stamping operation. This forming process and the apparatus used therefor, however, does not form part of our present patent application.

The portions 36 of the riser are provided with lateral corrugations 38. The corrugations 38 have no special function in the device, but are of importance in the process of making the riser.

In assembling the foil l6 and riser ll, the foil I6 is placed directly over the rivets 32 and the rivets are spun therethrough forming thereby their own holes in the foil with the aid of the sharp edge formed by their conical recess'SO; this makes it unnecessary to provide the foil beforehand with holes.

While we have described our invention in connection with specific examples and in specific applications, it should be well understood that we do not wish to be limited thereto, but desire the lap-- pended claims tobe construed as broadly as permissible in view of the prior art.

What we claim is: K 1. In an electrolytic condenser, an anode as sembly comprising a foil and a supporting riser for same, said riser having a flattened portion adjacent to the electrode foil, and a plurality of projecting portions on said flattened portion, and rivets extending from said projecting portions,

, said projecting portions and rivets being integral with said riser and securing said foil to said riser in spaced relationship.

- 2. An electrode riser consisting of an aluminum wire flattened at one end, a plurality of rivets integral with and extending from said flattened portion, and ribs formed on the riser in the rear of said rivets to increase the rigidity of the riser.

3. An electrode riser for electrolytic devices. comprising a rod member and integral rivets formed on said rod member, said rivets being provlded' with distancing shoulders.

4. In the manufacture of electrolytic devicu. the process which comprises, securing an electrode foil to an anode riser by piercing through said electrode foils perforations with projections provided on said riser, riveting said foil to said riser by means of said projections, and maintaining the electrode surface in non-contacting relation with the riser in its entire portion not flxedly' secured to the riser.

5. In an electrolytic condenser, an.an ode assembly comprising a foil add a rod-shaped sup-- porting riser for same, said riser comprising a flattened portion, a plurality of ofi'set portions provided on one side of said flattened portion. a plurality ofrivets integral with and extending from said offset portions, and means to increase the rigidity of said riser, said means comprising ribs formed on said flattened portion at the rear and on the opposite side 'of said ofi'set portions. 

